Roles of Nrf2 in Gastric Cancer: Targeting for Therapeutic Strategies

The role of TMSB15A in gastric cancer progression and its prognostic significance

Background

Human thymosin β15 (TMSB15A) has been found to have protumorigenic effects in various malignant tumors, yet its function in gastric cancer (GC) remains unclear. This study investigated the value and function of TMSB15A in the diagnosis and tumorigenesis of GC, respectively.

Methods

Expression data for TMSB15A in GC tissues were analyzed using The Cancer Genome Atlas (TCGA). We evaluated the prognostic significance of TMSB15A through Kaplan-Meier survival analysis, time-dependent receiver operating characteristic (ROC) curves, and Cox regression models. Gene set enrichment analysis (GSEA) was performed to identify pathways associated with TMSB15A. In vitro assays assessed the effects of TMSB15A knockdown on GC cell proliferation, migration, and invasion.

Results

TMSB15A was significantly overexpressed in GC tissues compared to normal tissues (P<0.05). ROC analysis showed high diagnostic accuracy for TMSB15A (area under the curve =0.851, 95% confidence interval: 0.786-0.905, P<0.05). Kaplan-Meier survival analysis revealed that high TMSB15A expression was associated with poor overall survival, disease-specific survival, and progression-free survival. TMSB15A levels were correlated with advanced tumor stages (P<0.05), lymph node metastasis (P<0.01), and perineural invasion (P<0.05). GSEA showed significant enrichment of TMSB15A in inflammatory and oncogenic pathways, including interleukin-6 (IL-6)/Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3), transforming growth factor β (TGF-β), and Hedgehog. Functional assays demonstrated that TMSB15A knockdown significantly reduced GC cell proliferation, migration, and invasion, suggesting that TMSB15A contributes to GC tumorigenesis and metastasis.

Conclusions

TMSB15A could serve as a prospective therapeutic target for GC due to its involvement in disease progression and metastasis.

Reversal of chemotherapy resistance in gastric cancer with traditional Chinese medicine as sensitizer: potential mechanism of action

Gastric cancer (GC) remains one of the most common types of cancer, ranking fifth among cancer-related deaths worldwide. Chemotherapy is an effective treatment for advanced GC. However, the development of chemotherapy resistance, which involves the malfunction of several signaling pathways and is the consequence of numerous variables interacting, seriously affects patient treatment and leads to poor clinical outcomes. Therefore, in order to treat GC, it is imperative to find novel medications that will increase chemotherapy sensitivity and reverse chemotherapy resistance. Traditional Chinese medicine (TCM) has been extensively researched as an adjuvant medication in recent years. It has been shown to have anticancer benefits and to be crucial in enhancing chemotherapy sensitivity and reducing chemotherapy resistance. Given this, the mechanism of treatment resistance in GC is summed up in this work. The theoretical foundation for TCM as a sensitizer in adjuvant treatment of GC is established by introducing the primary signal pathways and possible targets implicated in improving chemotherapy sensitivity and reversing chemotherapy resistance of GC by TCM and active ingredients.

Immunotherapy in gastric cancer-A systematic review

Background

Gastric Cancer (GC) is the 5th most prevalent and 4th most deadly neoplasm globally. Immunotherapy has emerged as a promising treatment approach in GC, potentially improving positive clinical outcomes while addressing the limitations of conventional therapies. GC immunotherapy modalities consist of adoptive cell therapy (ACT), cancer vaccines, and immune checkpoint inhibitors (ICI).

Objectives

This systematic review aims to provide an overview of the advances in immune-based therapeutic approaches in GC, highlighting the potential of this therapy as a strategy for GC treatment.

Methods

Key studies investigating several immunotherapeutic agents and combination therapies were searched in PUBMED and included in this study. Specific cancer outcomes related to disease progression or survival were analyzed.

Results

After screening 236 studies, the results revealed that immunotherapy, particularly the ICI pembrolizumab, demonstrated promising efficacy in the treatment of GC, as several studies reported improved OS, PFS, and objective response rate with the use of pembrolizumab alone or in combination with other treatment modalities.

Conclusion

Safety analysis showed that immunotherapy was mostly well-tolerated, with manageable adverse events and relatively good safety profiles. Nonetheless, further research is required to understand the mechanisms of tumor resistance better and identify predictive biomarkers that can direct treatment optimization.

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

Co-targeting NRF2 potentially enhances the in vitro anticancer effects of paclitaxel in gastric cancer cells

BACKGROUND

Gastric cancer (GC) is a highly chemoresistant malignancy with a poor prognosis. Paclitaxel's low response rate as second-line chemotherapy for advanced GC has prompted intensive research into its molecular basis and prospective targeted therapies to enhance its therapeutic efficacy. The objective of this study was to investigate the synergistic effects of NRF2 silencing in combination with paclitaxel treatment on GC cell viability, apoptosis, proliferation, autophagy, and migration.

METHODS

\After the siRNA-mediated silencing of NRF2 in AGS cells, the transfection efficacy was evaluated by qRT-PCR. The MTT assay was then applied to assess cell viability, followed by flow cytometry analysis for apoptosis, proliferation, and autophagy in AGS cells treated with NRF2 siRNA, paclitaxel, or their combination. Thereafter, the migration of cells was measured using a wound-healing assay. Ultimately, the relative gene expression levels of apoptotic (Bax, Caspase-3, and Caspase-9), anti-apoptotic (Bcl-2), metastatic (MMP-2), and cell cycle (P53) genes were measured by qRT-PCR in all experiment groups to further assess the molecular basis for the combination therapy.

RESULTS

NRF2 siRNA transfection significantly enhanced paclitaxel-induced apoptosis and sensitized AGS cells to paclitaxel via modulating the expression of apoptosis-related genes including Bcl-2, Bax, Caspase-3, and Caspase-9. Besides, NRF2 siRNA and paclitaxel synergistically induced cell cycle arrest at the G2 phase, promoted autophagy activation, and inhibited AGS cell migration via MMP-2 downregulation. Additionally, P53, a key regulator of cell growth, was significantly upregulated in the treated groups compared to the control group.

CONCLUSIONS

Our findings suggest that paclitaxel combined with siRNA-mediated silencing of NRF2 might represent a promising therapeutic strategy for GC, however further translational and clinical research are warranted.

Vorinostat Treatment of Gastric Cancer Cells Leads to ROS-Induced Cell Inhibition and a Complex Pattern of Molecular Alterations in Nrf2-Dependent Genes

Histone deacetylase inhibitors (HDACi) show high antineoplastic potential in preclinical studies in various solid tumors, including gastric carcinoma; however, their use in clinical studies has not yet yielded convincing efficacies. Thus, further studies on cellular/molecular effects of HDACi are needed, for improving clinical efficacy and identifying suitable combination partners. Here, we investigated the role of oxidative stress in gastric cancer cells upon treatment with HDACi. A particular focus was laid on the role of the Nrf2 pathway, which can mediate resistance to cell-inhibitory effects of reactive oxidative species (ROS). Using fluorescence-based ROS sensors, oxidative stress was measured in human gastric cancer cell lines. Activation of the Nrf2 pathway was monitored in luciferase reporter assays as well as by mRNA and proteomic expression analyses of Nrf2 regulators and Nrf2-induced genes. Furthermore, the effects of ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2-knockdown on HDACi-dependent antiproliferative effects were investigated in colorimetric formazan-based and clonogenic survival assays. HDACi treatment led to increased oxidative stress levels and consequently, treatment with NAC reduced cytotoxicity of HDACi. In addition, vorinostat treatment stimulated expression of a luciferase reporter under the control of an antioxidative response element, indicating activation of the Nrf2 system. This Nrf2 activation was only partially reversible by treatment with NAC, suggesting ROS independent pathways to contribute to HDACi-promoted Nrf2 activation. In line with its cytoprotective role, Nrf2 knockdown led to a sensitization against HDACi. Accordingly, the expression of antioxidant and detoxifying Nrf2 target genes was upregulated upon HDACi treatment. In conclusion, oxidative stress induction upon HDAC inhibition contributes to the antitumor effects of HDAC inhibitors, and activation of Nrf2 represents a potentially important adaptive response of gastric cancer cells in this context.

Meningioma achieves malignancy and erastin-induced ferroptosis resistance through FOXM1-AURKA-NRF2 axis

The oncogene Aurora kinase A (AURKA) has been implicated in various tumor, yet its role in meningioma remains unexplored. Recent studies have suggested a potential link between AURKA and ferroptosis, although the underlying mechanisms are unclear. This study presented evidence of AURKA upregulation in high grade meningioma and its ability to enhance malignant characteristics. We identified AURKA as a suppressor of erastin-induced ferroptosis in meningioma. Mechanistically, AURKA directly interacted with and phosphorylated kelch-like ECH-associated protein 1 (KEAP1), thereby activating nuclear factor erythroid 2 related factor 2 (NFE2L2/NRF2) and target genes transcription. Additionally, forkhead box protein M1 (FOXM1) facilitated the transcription of AURKA. Suppression of AURKA, in conjunction with erastin, yields significant enhancements in the prognosis of a murine model of meningioma. Our study elucidates an unidentified mechanism by which AURKA governs ferroptosis, and strongly suggests that the combination of AURKA inhibition and ferroptosis-inducing agents could potentially provide therapeutic benefits for meningioma treatment.

Natural xanthones as modulators of the Nrf2/ARE signaling pathway and potential gastroprotective agents

Oxidative stress is implicated in the initiation, pathogenesis, and progression of various gastric inflammatory diseases (GID). The prevalence of these diseases remains a concern along with the increasing risks of adverse effects in current clinical interventions. Hence, new gastroprotective agents capable of inhibiting oxidative stress by modulating cellular defense systems such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway are critically needed to address these issues. A candidate to solve the present issue is xanthone, a natural compound that reportedly exerts gastroprotective effects via antioxidant, anti-inflammatory, and cytoprotective mechanisms. Moreover, xanthone derivatives were shown to modulate the Nrf2/ARE signaling pathway to counter oxidative stress in both in vitro and in vivo models. Thirteen natural xanthones have demonstrated the ability to modulate the Nrf2/ARE signaling pathway and have high potential as lead compounds for GID as indicated by their in vivo gastroprotective action-particularly mangiferin (2), α-mangostin (3), and γ-mangostin (4). Further studies on these compounds are recommended to validate the Nrf2 modulatory ability in relation to their gastroprotective action.

Fibroblast growth factor receptor-4 mediates activation of Nuclear Factor Erythroid 2-Related Factor-2 in gastric tumorigenesis

Helicobacter pylori (H. pylori) is the leading risk factor for gastric carcinogenesis. Fibroblast growth factor receptor 4 (FGFR4) is a member of transmembrane tyrosine kinase receptors that are activated in cancer. We investigated the role of FGFR4 in regulating the cellular response to H. pylori infection in gastric cancer. High levels of oxidative stress signature and FGFR4 expression were detected in gastric cancer samples. Gene set enrichment analysis (GSEA) demonstrated enrichment of NRF2 signature in samples with high FGFR4 levels. H. pylori infection induced reactive oxygen species (ROS) with a cellular response manifested by an increase in FGFR4 with accumulation and nuclear localization NRF2. Knocking down FGFR4 significantly reduced NRF2 protein and transcription activity levels, leading to higher levels of ROS and DNA damage following H. pylori infection. We confirmed the induction of FGFR4 and NRF2 levels using mouse models following infection with a mouse-adapted H. pyloristrain. Pharmacologic inhibition of FGFR4 using H3B-6527, or its knockdown, remarkably reduced the level of NRF2 with a reduction in the size and number of gastric cancer spheroids. Mechanistically, we detected binding between FGFR4 and P62 proteins, competing with NRF2-KEAP1 interaction, allowing NRF2 to escape KEAP1-dependent degradation with subsequent accumulation and translocation to the nucleus. These findings demonstrate a novel functional role of FGFR4 in cellular homeostasis via regulating the NRF2 levels in response to H. pylori infection in gastric carcinogenesis, calling for testing the therapeutic efficacy of FGFR4 inhibitors in gastric cancer models.

Synthesis, Pharmacological Properties, and Potential Molecular Mechanisms of Antitumor Activity of Betulin and Its Derivatives in Gastrointestinal Cancers

Gastrointestinal (GI) cancers are an increasingly common type of malignancy, caused by the unhealthy lifestyles of people worldwide. Limited methods of treatment have prompted the search for new compounds with antitumor activity, in which betulin (BE) is leading the way. BE as a compound is classified as a pentacyclic triterpene of the lupane type, having three highly reactive moieties in its structure. Its mechanism of action is based on the inhibition of key components of signaling pathways associated with proliferation, migration, interleukins, and others. BE also has a number of biological properties, i.e., anti-inflammatory, hepatoprotective, neuroprotective, as well as antitumor. Due to its poor bioavailability, betulin is subjected to chemical modifications, obtaining derivatives with proven enhanced pharmacological and pharmacokinetic properties as a result. The method of synthesis and substituents significantly influence the effect on cells and GI cancers. Moreover, the cytotoxic effect is highly dependent on the derivative as well as the individual cell line. The aim of this study is to review the methods of synthesis of BE and its derivatives, as well as its pharmacological properties and molecular mechanisms of action in colorectal cancer, hepatocellular carcinoma, gastric cancer, and esophageal cancer neoplasms.

Effects of oxidative stress regulation in inflammation-associated gastric cancer progression treated using traditional Chinese medicines: A review

Gastric cancer (GC) is a global public health concern that poses a serious threat to human health owing to its high morbidity and mortality rates. Due to the lack of specificity of symptoms, patients with GC tend to be diagnosed at an advanced stage with poor prognosis. Therefore, the development of new treatment methods is particularly urgent. Chronic atrophic gastritis (CAG), a precancerous GC lesion, plays a key role in its occurrence and development. Oxidative stress has been identified as an important factor driving the development and progression of the pathological processes of CAG and GC. Therefore, regulating oxidative stress pathways can not only intervene in CAG development but also prevent the occurrence and metastasis of GC and improve the prognosis of GC patients. In this study, PubMed, CNKI, and Web of Science were used to search for a large number of relevant studies. The review results suggested that the active ingredients of traditional Chinese medicine (TCM) and TCM prescriptions could target and improve inflammation, pathological status, metastasis, and invasion of tumor cells, providing a potential new supplement for the treatment of CAG and GC.

Therapeutic potentials of cannabidiol: Focus on the Nrf2 signaling pathway

Cannabidiol (CBD), a cannabinoid that does not create psychoactive activities, has been identified as having a multitude of therapeutic benefits. This study delves into the chemical properties, pharmacokinetics, safety and toxicity, pharmacological effects, and most importantly, the association between the therapeutic potential of CBD and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. The relationship between Nrf2 and CBD is closely linked to certain proteins that are associated with cardiovascular dysfunctions, cancers, and neurodegenerative conditions. Specifically, Nrf2 is connected to the initiation and progression of diverse health issues, including nephrotoxicity, bladder-related diseases, oral mucositis, cancers, obesity, myocardial injury and angiogenesis, skin-related inflammations, psychotic disorders, neuropathic pain, Huntington's disease, Alzheimer's disease, Parkinson's disease, neuroinflammation, Amyotrophic Lateral Sclerosis, and Multiple Sclerosis. The association between CBD and Nrf2 is a zone of great interest in the medical field, as it has the potential to significantly impact the treatment and prevention of wide-ranging health conditions. Additional investigation is necessary to entirely apprehend the mechanisms underlying this crucial interplay and to develop effective therapeutic interventions.

Nrf2 signaling pathway: current status and potential therapeutic targetable role in human cancers

Cancer is a borderless global health challenge that continues to threaten human health. Studies have found that oxidative stress (OS) is often associated with the etiology of many diseases, especially the aging process and cancer. Involved in the OS reaction as a key transcription factor, Nrf2 is a pivotal regulator of cellular redox state and detoxification. Nrf2 can prevent oxidative damage by regulating gene expression with antioxidant response elements (ARE) to promote the antioxidant response process. OS is generated with an imbalance in the redox state and promotes the accumulation of mutations and genome instability, thus associated with the establishment and development of different cancers. Nrf2 activation regulates a plethora of processes inducing cellular proliferation, differentiation and death, and is strongly associated with OS-mediated cancer. What's more, Nrf2 activation is also involved in anti-inflammatory effects and metabolic disorders, neurodegenerative diseases, and multidrug resistance. Nrf2 is highly expressed in multiple human body parts of digestive system, respiratory system, reproductive system and nervous system. In oncology research, Nrf2 has emerged as a promising therapeutic target. Therefore, certain natural compounds and drugs can exert anti-cancer effects through the Nrf2 signaling pathway, and blocking the Nrf2 signaling pathway can reduce some types of tumor recurrence rates and increase sensitivity to chemotherapy. However, Nrf2's dual role and controversial impact in cancer are inevitable consideration factors when treating Nrf2 as a therapeutic target. In this review, we summarized the current state of biological characteristics of Nrf2 and its dual role and development mechanism in different tumor cells, discussed Keap1/Nrf2/ARE signaling pathway and its downstream genes, elaborated the expression of related signaling pathways such as AMPK/mTOR and NF-κB. Besides, the main mechanism of Nrf2 as a cancer therapeutic target and the therapeutic strategies using Nrf2 inhibitors or activators, as well as the possible positive and negative effects of Nrf2 activation were also reviewed. It can be concluded that Nrf2 is related to OS and serves as an important factor in cancer formation and development, thus provides a basis for targeted therapy in human cancers.

Natural products targeting signaling pathways associated with regulated cell death in gastric cancer: Recent advances and perspectives

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with high morbidity and mortality. The complexity of GC process lies in the multi-phenotypic linkage regulation, in which regulatory cell death (RCD) is the core link, which largely dominates the fate of GC cells and becomes a key determinant of GC development and prognosis. In recent years, increasing evidence has been reported that natural products can prevent and inhibit the development of GC by regulating RCDs, showing great therapeutic potential. In order to further clarify its key regulatory characteristics, this review focused on specific expressions of RCDs, combined with a variety of signaling pathways and their crosstalk characteristics, sorted out the key targets and action rules of natural products targeting RCD. It is highlighted that a variety of core biological pathways and core targets are involved in the decision of GC cell fate, including the PI3K/Akt signaling pathway, MAPK-related signaling pathways, p53 signaling pathway, ER stress, Caspase-8, gasdermin D (GSDMD), and so on. Moreover, natural products target the crosstalk of different RCDs by modulating above signaling pathways. Taken together, these findings suggest that targeting various RCDs in GC with natural products is a promising strategy, providing a reference for further clarifying the molecular mechanism of natural products treating GC, which warrants further investigations in this area.

Mitigation of Cardiovascular Disease and Toxicity through NRF2 Signalling

Cardiovascular toxicity and diseases are phenomena that have a vastly detrimental impact on morbidity and mortality. The pathophysiology driving the development of these conditions is multifactorial but commonly includes the perturbance of reactive oxygen species (ROS) signalling, iron homeostasis and mitochondrial bioenergetics. The transcription factor nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2), a master regulator of cytoprotective responses, drives the expression of genes that provide resistance to oxidative, electrophilic and xenobiotic stresses. Recent research has suggested that stimulation of the NRF2 signalling pathway can alleviate cardiotoxicity and hallmarks of cardiovascular disease progression. However, dysregulation of NRF2 dynamic responses can be severely impacted by ageing processes and off-target toxicity from clinical medicines including anthracycline chemotherapeutics, rendering cells of the cardiovascular system susceptible to toxicity and subsequent tissue dysfunction. This review addresses the current understanding of NRF2 mechanisms under homeostatic and cardiovascular pathophysiological conditions within the context of wider implications for this diverse transcription factor.

Periplocin exerts antitumor activity by regulating Nrf2-mediated signaling pathway in gemcitabine-resistant pancreatic cancer cells

Although gemcitabine-based chemotherapy is common and effective for pancreatic cancer (PC), acquired drug resistance is one of the major reasons for treatment failure. Therefore, a novel therapeutic approach for gemcitabine-resistant PC is required. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an oxidative stress-responsive transcription factor regulating antioxidant responses and plays a crucial role in chemoresistance. In the present study, the antitumor activity of periplocin, a natural cardiac glycoside, was evaluated in an established gemcitabine-resistant PC cell line (PANC-GR). Nrf2 was overexpressed in gemcitabine-resistant cells, and Nrf2 knockdown recovered gemcitabine sensitivity in PANC-GR cells. The antiproliferative activity of periplocin was highly associated with Nrf2 downregulation and Nrf2-mediated signaling pathways in PANC-GR cells. Periplocin also increased reactive oxygen species production inducing G₀/G₁ cell cycle arrest and apoptosis in PANC-GR cells. Periplocin and gemcitabine combined significantly inhibited tumor growth in a PANC-GR cells-implanted xenograft mouse model via Nrf2 downregulation. Overall, these findings suggest that periplocin might be a novel therapeutic agent against gemcitabine resistance, as it could recover sensitivity to gemcitabine by regulating Nrf2-mediated signaling pathways in gemcitabine-resistant PC cells.

Hawk Tea Flavonoids as Natural Hepatoprotective Agents Alleviate Acute Liver Damage by Reshaping the Intestinal Microbiota and Modulating the Nrf2 and NF-κB Signaling Pathways

Hawk tea (Litsea coreana Levl. var. lanuginosa) is a traditional herbal tea in southwestern China, and was found to possess hepatoprotective effects in our previous study. However, it is unclear whether hawk tea flavonoids (HTF) can alleviate alcoholic liver damage (ALD). Firstly, we extracted and identified the presence of 191 molecules categorized as HTFs, with reynoutrin, avicularin, guaijaverin, cynaroside, and kaempferol-7-O-glucoside being the most prevalent. After taking bioavailability into consideration and conducting comprehensive sorting, the contribution of guaijaverin was the highest (0.016 mg/mice). Then, by daily intragastric administration of HTF (100 mg/kg/day) to the ALD mice, we found that HTF alleviated liver lipid deposition (inhibition of TG, TC, LDL-C) by reducing liver oxidative-stress-mediated inflammation (up-regulation NRF2/HO-1 and down-regulation TLR4/MyD88/NF-κB pathway) and reshaping the gut microbiota (Lactobacillus, Bifidobacterium, Bacillus increased). Overall, we found HTF could be a potential protective natural compound for treating ALD via the gut–liver axis and guaijaverin might be the key substance involved.

The Role of Concomitant Nrf2 Targeting and Stem Cell Therapy in Cerebrovascular Disease

Despite the reality that a death from cerebrovascular accident occurs every 3.5 min in the United States, there are few therapeutic options which are typically limited to a narrow window of opportunity in time for damage mitigation and recovery. Novel therapies have targeted pathological processes secondary to the initial insult, such as oxidative damage and peripheral inflammation. One of the greatest challenges to therapy is the frequently permanent damage within the CNS, attributed to a lack of sufficient neurogenesis. Thus, recent use of cell-based therapies for stroke have shown promising results. Unfortunately, stroke-induced inflammatory and oxidative damage limit the therapeutic potential of these stem cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been implicated in endogenous antioxidant and anti-inflammatory activity, thus presenting an attractive target for novel therapeutics to enhance stem cell therapy and promote neurogenesis. This review assesses the current literature on the concomitant use of stem cell therapy and Nrf2 targeting via pharmaceutical and natural agents, highlighting the need to elucidate both upstream and downstream pathways in optimizing Nrf2 treatments in the setting of cerebrovascular disease.

Microbial metabolite restricts 5-fluorouracil-resistant colonic tumor progression by sensitizing drug transporters via regulation of FOXO3-FOXM1 axis

The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil (5FU). Although there is mounting evidence that commensal gut microbiota is essential for effective colon cancer treatment, the detailed molecular mechanisms and the role of gut microbial metabolites remain elusive. The goal of this study is to decipher the impact and mechanisms of gut microbial metabolite, urolithin A (UroA) and its structural analogue, UAS03 on reversal of 5FU-resistant (5FUR) colon cancers. Methods: We have utilized the SW480 and HCT-116 parental (5FU-sensitive) and 5FUR colon cancer cells to examine the chemosensitization effects of UroA or UAS03 by using both in vitro and in vivo models. The effects of mono (UroA/UAS03/5FU) and combinatorial therapy (UroA/UAS03 + 5FU) on cell proliferation, apoptosis, cell migration and invasion, regulation of epithelial mesenchymal transition (EMT) mediators, expression and activities of drug transporters, and their regulatory transcription factors were examined using molecular, cellular, immunological and flowcytometric methods. Further, the anti-tumor effects of mono/combination therapy (UroA or UAS03 or 5FU or UroA/UAS03 + 5FU) were examined using pre-clinical models of 5FUR-tumor xenografts in NRGS mice and azoxymethane (AOM)-dextran sodium sulfate (DSS)-induced colon tumors. Results: Our data showed that UroA or UAS03 in combination with 5FU significantly inhibited cell viability, proliferation, invasiveness as well as induced apoptosis of the 5FUR colon cancer cells compared to mono treatments. Mechanistically, UroA or UAS03 chemosensitized the 5FUR cancer cells by downregulating the expression and activities of drug transporters (MDR1, BCRP, MRP2 and MRP7) leading to a decrease in the efflux of 5FU. Further, our data suggested the UroA or UAS03 chemosensitized 5FUR cancer cells to 5FU treatment through regulating FOXO3-FOXM1 axis. Oral treatment with UroA or UAS03 in combination with low dose i.p. 5FU significantly reduced the growth of 5FUR-tumor xenografts in NRGS mice. Further, combination therapy significantly abrogated colonic tumors in AOM-DSS-induced colon tumors in mice. Conclusions: In summary, gut microbial metabolite UroA and its structural analogue UAS03 chemosensitized the 5FUR colon cancers for effective 5FU chemotherapy. This study provided the novel characteristics of gut microbial metabolites to have significant translational implications in drug-resistant cancer therapeutics.

3,4‑Dihydroxyacetophenone attenuates oxidative stress‑induced damage to HUVECs via regulation of the Nrf2/HO‑1 pathway

It has been reported that oxidative stress plays a prominent role in diabetic macrovascular diseases. 3,4-Dihydroxyacetophenone (3,4-DHAP) has been found to have a variety of biological activities. However, few studies have assessed the antioxidant capacity of 3,4-DHAP and the underlying mechanisms. Thus, the aim of the present study was to explore the effects of 3,4-DHAP on oxidative stress in human umbilical vein endothelial cells (HUVECs). HUVECs were pre-treated with 3,4-DHAP and then exposed to high glucose conditions. Cell viability and cytotoxicity were measured using an MTT assay. Reactive oxygen species (ROS) levels were measured using an inverted fluorescence microscope and a fluorescent enzyme labeling instrument. Protein expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), microtubule-associated protein 1A/1B-light chain 3 (LC3) and poly ADP-ribose polymerase-1 (PARP-1) were measured using western blotting, and mRNA expression of Nrf2 and HO-1 were measured through reverse transcription-quantitative PCR (RT-qPCR). Nrf2 nuclear translocation was evaluated using immunofluorescence analysis and autophagosomes were observed using transmission electron microscope (TEM). The results of the present study demonstrated that compared with the control group, cell viability of the high glucose group was reduced and cell cytotoxicity of the high glucose group was increased. ROS production in the high glucose group was clearly enhanced. In addition, high glucose upregulated Nrf2 and HO-1 protein and mRNA expression levels. Nuclear translocation of Nrf2 in the high glucose group was also increased. The formation of autophagosomes in the high glucose group was also higher than that in the control group. Furthermore, LC3-II/LC3-I and PARP-1 protein expression levels were increased after treatment with high glucose. However, compared to the high glucose group, 3,4-DHAP (10 µmol/l) significantly enhanced cell viability. 3,4-DHAP markedly decreased the production of ROS, increased Nrf2 and HO-1 protein and mRNA expression levels, and promoted nuclear translocation of Nrf2 in HUVECs. In addition, 3,4-DHAP promoted the formation of autophagosomes, and notably increased the protein expression levels of LC3-II/LC3-I and PARP-1. Moreover, it was determined that compared to the 3,4-DHAP group, treatment with 3,4-DHAP and ML385 enhanced cell viability, and decreased ROS production, Nrf2 and HO-1 protein and mRNA expression levels, nuclear translocation of Nrf2, and LC3-II/LC3-I and PARP-1 protein expression levels. Collectively, the results of the present study showed that 3,4-DHAP protected HUVECs against oxidative stress via regulation of the Nrf2/HO-1 pathway, by increasing autophagy and promoting DNA damage repair.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system's response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

A systematic and meta-analysis study on the prevalence of tuberculosis and relative risk factors for prisoners in Iran

INTRODUCTION

This study aimed to evaluate the incidence of Tuberculosis (TB) among prisoners in Iran, by performing a systematic and meta-analysis study on the related articles.

METHODOLOGY

Scopus, Iran doc, Cochrane, Pubmed, Medline, Embase and Iran Medex, Magiran, SID, Google Scholar, and EBSCO were searched. After quality assessment of the articles, a fixed or random model, as appropriate, was used to pool the results in a meta-analysis. Heterogeneity between the studies was assessed using I-square and Q-test.

RESULTS

The overall sample size of included studies was 19562 that 64 of them were with TB. The highest prevalence of tuberculosis was related to the study of Rasht, 517 in 100,000 but the lowest rate was related to the study of Sought Khorasan, 25 in 100,000. The ES of the random effect model is 0.003 (95% CI, 0.001-0.005) and p-value <0.0001. The Higgins' I2 of all studies is 86.55%, and the p-value of the Cochrane Q statistics is <0.001, indicating that there is heterogeneity. Based on the Egger regression plot (t=2.18, p = 0.08, CI 95%: -0.001, 0.005) no publication bias existed.

CONCLUSION

The frequency of TB among the prisoners in Iran was low. Due to important limitations in this study, it is not possible to indicate the exact prevalence of TB among prisoners in Iran and compare this with the general population. More studies are needed to assess the related risk factor for designing health interventions plan to decrease the incidence rate of TB among prisoners.

Resveratrol as an Adjunctive Therapy for Excessive Oxidative Stress in Aging COVID-19 Patients

The coronavirus disease 2019 (COVID-19) pandemic continues to burden healthcare systems worldwide. COVID-19 symptoms are highly heterogeneous, and the patient may be asymptomatic or may present with mild to severe or fatal symptoms. Factors, such as age, sex, and comorbidities, are key determinants of illness severity and progression. Aging is accompanied by multiple deficiencies in interferon production by dendritic cells or macrophages in response to viral infections, resulting in dysregulation of inflammatory immune responses and excess oxidative stress. Age-related dysregulation of immune function may cause a more obvious pathophysiological response to SARS-CoV-2 infection in elderly patients and may accelerate the risk of biological aging, even after recovery. For more favorable treatment outcomes, inhibiting viral replication and dampening inflammatory and oxidative responses before induction of an overt cytokine storm is crucial. Resveratrol is a potent antioxidant with antiviral activity. Herein, we describe the reasons for impaired interferon production, owing to aging, and the impact of aging on innate and adaptive immune responses to infection, which leads to inflammation distress and immunosuppression, thereby causing fulminant disease. Additionally, the molecular mechanism by which resveratrol could reverse a state of excessive basal inflammatory and oxidative stress and low antiviral immunity is discussed.